Light and Sound. Wave Behavior and Interactions

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Ellen Woods
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1 Light and Sound Wave Behavior and Interactions

2 How do light/sound waves interact with matter?

3 WORD Definition Example Picture REFLECTED REFRACTED is the change in direction of a wave when it changes speed as it travels from one material(medium) to another. SCATTERING ABSORPTION TRANSMITTED The process by which materials take in light and change it into heat.

4 Think about it On a bright, sunny day which bench would you rather sit on? Black or White? Why?

5 WAVE DISTURBANCES All waves can be deflected, distorted or changed when they come in contact with a boundary.

6 WAVE DISTURBANCES When light interacts with matter it is either: absorbed

7 Absorption: Occurs when light waves transfer energy to particles of matter. Light stops at the object and does not reflect or refract.

8 ABSORPTION When incoming light hits an object it causes its atoms to vibrate. It then converts the energy into heat which is radiated.

9 Absorption and Color Why do you feel warmer when you wear a black shirt vs. wearing a white shirt?

10 Absorption and Color A black shirt absorbs all wavelengths of light, absorbing the energy and turning it to heat A white shirt reflects all wavelengths of light.

11 ABSORPTION Anyone with a dark-colored car on a hot day will experience the effects of absorption.

12 ABSORPTION The beam of light from this flashlight is being absorbed as it passes through matter. It becomes less intense the further it travels from the light source.

Instead, those light waves bounce off the surface, are transmitted to the human eye, and are

13 ABSORPTION When light hits a non-reflecting surface, the light waves are absorbed by the object. However, the light waves that are the same color as the object are not absorbed. Instead, those light waves bounce off the surface, are transmitted to the human eye, and are interpreted as the color of the object. yellow bananas, reflect only the yellow part of sunlight but absorb the light of all other colors.

14 When light interacts with matter it is either: absorbed transmitted

15 Transmission: Occurs when light waves pass through an object without interacting.

16 TRANSMISSION

17 When light interacts with matter it is either: absorbed transmitted refracted

$Refraction: is the change in direction of a wave when it$

18 Refraction: is the change in direction of a wave when it changes speed as it travels from one material(medium) to another.

19 REFRACTION

20 REFRACTION

21 REFRACTION

22 REFRACTION

23 REFRACTION

24 When light interacts with matter it is either: absorbed transmitted refracted reflected

25 Reflection: Occurs when light waves bounce off of an object.

26 REFLECTION

27 REFLECTION Bananas are yellow because the color yellow is being reflected off of the bananas. All of the other colors of light are being absorbed into the bananas.

28 Law of REFLECTION The law of reflection states that when a ray of light reflects off a surface, the angle of incidence is equal to the angle of reflection.

29 Sound waves reflect. echo

30 When light interacts with matter it is either: absorbed transmitted refracted reflected scattered (form of reflection)

31 Scattering: an interaction of light with matter that causes light to change direction. Light scatters in all directions. An example of scattering is when the sky is blue

32 This explains why the sky is blue? Sunlight reaches Earth's atmosphere and is scattered in all directions by all the gases and particles in the air. Blue light is scattered in all directions by the tiny molecules of air in Earth's atmosphere. Because blue has a short wave length, it is particularly susceptible to scattering as it bounces off gas particles of the air surrounding Earth. Red, yellow and orange hues are much longer wavelengths, which is why they are only visible in the sky when looking near or at the sun.

34 SCATTERING

35 Reflection vs. Scattering If you shine a narrow beam at a highly polished surface (like a mirror), you get a narrow beam of light reflected back off it If you shine a narrow beam of light at a rough surface, the light scatters in all directions

of incidence is equal to the angle of reflection), whether or not the surface is smooth.

36 Reflection vs. Scattering When light reflects off a surface, it obeys the law of reflection (the angle of incidence is equal to the angle of reflection), whether or not the surface is smooth. The light is reflecting off the flower to the water and then back to your eye. In the wavy water, the light is scattered so you do not see a perfect reflection.

$Diffraction:$ waves bend

37 Diffraction: Occurs when waves bend around a barrier.

$DIFFRACTION Diffraction$ around the moon when it is

38 DIFFRACTION Diffraction explains why you see a ring around the moon when it is bright. It also explains how holograms work.

39 DIFFRACTION

40 Can you identify each type of light interaction occurring?

42 When light interacts with matter it is either: absorbed transmitted refracted reflected scattered

3 Interactions of Light Waves

CHAPTER 22 3 Interactions of Light Waves SECTION The Nature of Light BEFORE YOU READ After you read this section, you should be able to answer these questions: How does reflection affect the way we see